01 May 2012

Ring of Fire Eclipse 2012 in Northern California

It's May, and that means it is almost time for the Moon to cast its shadow on the Earth and create a wonderful spectacle in the afternoon sky. On Sunday May 20th, we will experience a very significant Solar Eclipse, a very rare and exciting "Ring of Fire," also known as an Annular Eclipse.

The afternoon of Sunday 20th, much of the western United States will see a very deep partial eclipse of the Sun. But in a special path across Northern California and several western states, we will witness the Moon fully enclosed within the disk of the Sun, creating a beautiful "Ring of Fire" effect. This effect will only last about 4 minutes, and will only be visible from the special path. Earth-Sky has an excellent overview article about the eclipse. If you choose to remain in San Francisco, you will see a very deep (90%) eclipse of the Sun, but if you travel a few hours north, you will experience the full Annular effect.

The map shows the path of the Moon's shadow across Northern California. I plan to watch this eclipse from the Mt. Shasta area, and there are many more areas to go to see this event. If you wish to join me and the San Francisco Amateur Astronomers (SFAA), check this article on the Ring of Fire Road Trip or my past blog post. But you have lots of choices, and depending upon the weather outlook, you will want to have some mobility to get to a good viewing spot in case of (gasp!) clouds. Here is a much more detailed map from Eclipse-Maps.com.

One of the most important factors when preparing to watch an eclipse is eye protection. I encourage all readers to purchase specialized viewing equipment such as eclipse glasses or a shade 14 welder's filter. At all times, the intense radiation from the Sun can cause permanent eye damage and even blindness, and during an eclipse it is tempting to stare up at the Sun. However, with simple planning and preparation, you can enjoy the eclipse without any fear of damaging your eyesight. Mr. Eclipse has some valuable information about eye safety and resources for buying solar glasses.

I wish all of you clear skies and a great view of this special event.

Map courtesy of Eclipse-Maps.com.


Todd Berman said...

Do you know of a place to buy eclipse-viewing glasses in SF?

Todd Berman said...

Do you know a place to buy eclipse-viewing glasses in San Francisco?

The Urban Astronomer said...

Todd: Scope City in the North Point Shopping Center near Pier 39 has plenty.

-- Paul

Μάγια said...

hi and thanks for your useful information. I will be in SF this day but I cannot leave town, unfortunately. as i am not aware of the area at all, where you could recommend i could go to watch the eclipse? (i have one meeting finishing at 16:30 downtown and a dinner starting at 20:30 also downtown...) thanks!

The Urban Astronomer said...

hi Mayia - join the San Francisco Amateur Astronomers at Crissy Field where they will have solar telescopes. http://www.sfaa-astronomy.org/. The California Academy of Sciences will also have telescopes set up in front of their museum in Golden Gate Park.

-- Paul

Μάγια said...

Hi Paul!

thank you VERY much! that's great help! enjoy the eclipse! maya

Nancy said...

Hi Paul,

After hearing your interview on public radio this evening, I'm excited to view this eclipse! I'm willing to get out of the Bay Area for better viewing, but probably can't justify going all the way to Shasta. The Chico Observatory is having an event - do you know of any other viewings between SF and Chico? Neither of the Davis Clubs seem to be hosting anything yet.


The Urban Astronomer said...

hi Nancy - given the path of the Moon's shadow and annularity, Chico is probably the southern-most location where you will find big gatherings. I don' know of anything south of that. Closer on I-5 (but not as far as Mt. Shasta) is a big event happening at the Whiskeytown National Park near Lake Shasta and Redding. http://www.shastaastronomyclub.com/eclipse.html.

I hope you make it out to a big event! And if you feel like driving the extra hour, we'd welcome you at Mt. Shasta.

-- Paul

Baile said...

Hello Urban Astronomer,

Can you help me figure out the map ? I am driving north and want to see the real, full, annular eclipse. I have noticed the times of the eclipse diminishing from the center line. Does this mean any place from center line will be less than 100% eclipse ? Mount Shasta is a good bit away from the center iine, but you are heading there. Will it be 100% ring of fire that far from the center line?

Want to get somewhere where I can see the western sky, for the Sun will be low at 6:30. It is happening around 6:30 pacific time, yes, near the Shasta area.

Color me a bit confused and wanting to get accurate information. It is a long drive and investment and I want to do my best to see the full monty.

The Urban Astronomer said...

hi Baile - good question.

The center line is where you will see the 4 minutes of annularity with the Moon's disc exactly centered in the Sun. If you are north or south of the center line, the Moon will not be exactly centered. However, as long as you are in the broader path of annularity you will see the full annular effect (100% annularity). The times on the map show precisely how many minutes and seconds you will experience with the Moon fully inside the Sun.

By being a bit north (at Mt. Shasta) or south (Redding), you will lose a few seconds of annularity, but you will still get the full Ring of Fire, just a slight bit off-center.

We checked and the altitude of the Sun at maximum eclipse (19 degrees) will be perfectly fine to see from our location at Mt. Shasta.

Make sense?

- Paul

Leeanne said...

Hi, I want to thank you for all of your great information about the eclipse this weekend. We are driving to the Whiskey Town event near Redding but I'm still looking for a couple of pairs of the eclipse-viewing glasses, do you know of any place in the east bay to buy them?


Baile said...

Yep ! Thanks.

Kinda want to know if one can really perceive the "off center" part of the explanation. Going to be another 18 years before this happens again in the US. That puts me at around 80.

Want to make the most of this one.

Anonymous said...

Do you have an exact location?
SFAA site says "Marina Green" and you say Crissy Field. Those are both very general locations.

The Urban Astronomer said...

Hi Leeanne - I am sorry but I don't know of shops in the east bay where you can buy eclipse glasses. At the Whiskeytown-Shasta event (shasta astro club), they will have plenty of scopes pointed at the Sun, and I would expect they will have some eclipse glasses to share. Best of luck with that.

Hi Anonymous - the event will be at the far edge of Crissy Field nearest the Exploratorium and Marina, but it is indeed Crissy Field. You'll find my colleagues from the SFAA there. Enjoy!

-- Paul

Alex said...

Is there any group organized to view the eclipse at Lake Tahoe?

The Urban Astronomer said...

hi Alex - I am not sure who might be setting up at Lake Tahoe for the eclipse. I know that amateurs will have telescopes in Reno/Sparks. Richard, who writes this blog: http://sidewalkuniverse.blogspot.com/, will be set up somewhere in the area. Here is another option: http://www.visitrenotahoe.com/reno-tahoe/what-to-do/events/05-20-2012/eclipse-viewing-

Best of luck.

-- Paul